Its meaning is described in the Bhagavata , Anushanaparva of Mahabharat and Vayupurana. Thirtha is a holy pilgrimage place especially on or near the banks of a sacred river or lake or by the sea. Kshetra is a sacred spot in other places.
One of the special meaning for the word “thirtha” is that whichever purifies is “thirtha”. Whoever does it are called “thirtharoopa” or “mahapurush”. According to the opinion of Manu even in the right ear of a Brahmin there are Sarva Thirthas. The holy feet of parents are thirtha & once own body itself is thirtha.
A thirtha yatra enables one to free one’s mind from the obsessions of all worldly matters. Realisation of purity of heart – “ Antahkarana Shuddhi ” is the first objective of thirtha yatra. It is only through antahkarana shuddhi that we would be able to realise vairagya and bhakti. Purity of heart arouses greater curiosity to know more about the Supreme Lord. Thus thirtha yatra is the first step in the series of steps of the “Sadhana marga”.